Certified GKH Gardening Expert
Bud drop in many plants can be caused by overwatering. If the container your plant is in is very large, overwatering is actually the most likely explanation. Plants in too-large containers can suffer from root damage and many other overwatering-related problems because the soil stays wet too long in a large container.
Other problems that can cause bud drop include pests on the plant or underwatering (if it's underwatered, the plant will appear wilted but they perk up when you water it).